The Short Sword 'Dagmor' (1d7) (+13,+11)
+2 attack speed. Slays animals. Branded with venom. Cannot be harmed by acid, electricity, fire, cold. Slows your metabolism. Speeds regeneration.
Min Level 20, Max Level 80, Generation chance 12, 8.0 lbs

(Angband 3.1.2v2)